Breakdown of Cortical Effective Connectivity During Sleep
2005; American Association for the Advancement of Science; Volume: 309; Issue: 5744 Linguagem: Inglês
10.1126/science.1117256
ISSN1095-9203
AutoresMarcello Massimini, Fabio Ferrarelli, Reto Huber, Steve K. Esser, Harpreet Singh, Giulio Tononi,
Tópico(s)Sleep and Wakefulness Research
ResumoWhen we fall asleep, consciousness fades yet the brain remains active. Why is this so? To investigate whether changes in cortical information transmission play a role, we used transcranial magnetic stimulation together with high-density electroencephalography and asked how the activation of one cortical area (the premotor area) is transmitted to the rest of the brain. During quiet wakefulness, an initial response (∼15 milliseconds) at the stimulation site was followed by a sequence of waves that moved to connected cortical areas several centimeters away. During non–rapid eye movement sleep, the initial response was stronger but was rapidly extinguished and did not propagate beyond the stimulation site. Thus, the fading of consciousness during certain stages of sleep may be related to a breakdown in cortical effective connectivity.
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